Researchers at the University of Western Ontario (Canada) have reported the development of graphene nanosheets (GNSs) as electrodes for nonaqueous lithium-oxygen batteries, which yield superior energy capacity [Y. Li et al., Chem Comm doi: (2011) 47, 9438]. Such nonaqueous lithium-oxygen/air batteries are one of the most promising energy storage systems for the next generation of hybrid-electric and electric vehicles.
It is reported that the battery performance strongly depended on the carbon cathode; led by Professor Xueliang (Andy) Sun, the researchers investigated graphene nanosheets as active cathode materials and found that the capacity of the battery could be significantly improved.
“The GNSs were applied in the nonaqueous lithium-oxygen battery, and the novel electrode delivered a capacity of 8705.9 mAh g-1, which is the highest capacity of any carbon-based material in lithium-oxygen batteries ever reported,” said Xueliang Sun, Professor in the Engineering Faculty.
The GNSs synthesized by Sun’s team possess a curly morphology with a thin, wrinkled structure. They discovered that these unique structures provide the ideal porosity for electrolyte wetting and the O2 diffusion, thus improving the discharge capacity dramatically.
The team also found that the large numbers of unsaturated carbon atoms at the edges of the GNSs, which are highly active and form oxygen-containing groups, contributed to the battery performance.
According to Xueliang, the finding “reveals that GNSs show [promise for] applications in lithium-oxygen batteries”.
Yongliang Li